Maximising access to thrombectomy services for stroke in England: A modelling study

Abstract

Both intravenous thrombolysis (IVT) and intra-arterial endovascular thrombectomy (ET) improve the outcome of patients with acute ischaemic stroke, with endovascular thrombectomy being an option for those patients with large vessel occlusions. We sought to understand how organisation of services affects time to treatment for both intravenous thrombolysis and endovascular thrombectomy. Method: A multi-objective optimisation approach was used to explore the relationship between the number of intravenous thrombolysis and endovascular thrombectomy centres and times to treatment. The analysis is based on 238,887 emergency stroke admissions in England over 3 years (2013-2015). Results: Providing hyper-acute care only in comprehensive stroke centres (CSC, providing both intravenous thrombolysis and endovascular thrombectomy, and performing >150 endovascular thrombectomy per year, maximum 40 centres) in England would lead to 15% of patients being more than 45 min away from care, and would create centres with up to 4300 stroke admissions/year. Mixing hyper-acute stroke units (providing intravenous thrombolysis only) with comprehensive stroke centres speeds time to intravenous thrombolysis and mitigates admission numbers to comprehensive stroke centres, but at the expense of increasing time to endovascular thrombectomy. With 24 comprehensive stroke centres and all remaining current acute stroke units as hyperacute stroke units, redirecting patients directly to attend a comprehensive stroke centre by accepting a small delay (15-min maximum) in intravenous thrombolysis reduces time to endovascular thrombectomy: 25% of all patients would be redirected from hyper-acute stroke units to a comprehensive stroke centre, with an average delay in intravenous thrombolysis of 8 min, and an average improvement in time to endovascular thrombectomy of 80 min. The balance of comprehensive stroke centre:hyper-acute stroke unit admissions would change from 24:76 to 49:51. Conclusion: Planning of hyper-acute stroke services is best achieved when considering all forms of acute care and ambulance protocol together. Times to treatment need to be considered alongside manageable and sustainable admission numbers.

Geographic Access to Stroke Care Services in Rural Communities in Ontario, Canada

“…[29][30][31][32][33][34][35][36] Direct transportation to intervention centers may be preferable to interhospital transfers, which can be associated with delays in treatment and worse outcomes. 23,[37][38][39] The designation of additional endovascular centers in underserved areas may be part of the solution, although it may be challenging to maintain a roster of staff and neurocritical care services in such areas, and one Korean study found that outcomes were worse at small-volume compared to large-volume sites. 40 Finally, allowing patients to seek care across provincial boundaries may reduce travel time to stroke care services.…”

Using Best-Worst Scaling to Understand the Preferences of Stroke Survivors, their Relatives/Carers and the Public on Providing Stroke Thrombectomy Services in England

“…Previous modelling studies indicated that increasing the number of CSCs from 24 (current number in England) to 30 would deliver both greatly enhanced population access to EVT plus health gains with a very high probability of being cost-effective [19,20]. Therefore, three outcomes with levels informed by 24 and 30 CSCs were included as attributes in the modelled BWS task: (1) clinical effectiveness of EVT; (2) cost of setting up, maintaining and running CSCs; and (3) equity of access to EVT for eligible patients.…”

“…Like angiography suites for EVT, additional MRI machines involves the provision of hi-tech expensive imaging infrastructure with multiple different staff groups required to run them, yet is an item which would be at least somewhat familiar to many, even most, respondents. Costs were estimated via in-house costing work (HL) based on published data [11,19,[31][32][33][34][35][36][37][38] and expert opinion. Equity was operationalised as proportions of patients with and without access to thrombectomy within 7 hours since onset of stroke symptoms.…”

“…However, due to a range of issues such as the lack of robust strati cation tools for use in the pre-hospital phase by paramedics [17], a drip and ship model (treatment with IVT at the nearest HASU before transfer to a CSC for EVT) was found to be the most preferred service con guration amongst professionals [18]. In a previous modelling study [19] using genetic algorithms, one optimal solution to expedite EVT within the drip and ship paradigm would be to increase the number of CSCs providing EVT in England. A modest geographically targeted increase, for instance from 24 to 30 centres, has been indicated as maximising the population gains [19,20].…”

“…In a previous modelling study [19] using genetic algorithms, one optimal solution to expedite EVT within the drip and ship paradigm would be to increase the number of CSCs providing EVT in England. A modest geographically targeted increase, for instance from 24 to 30 centres, has been indicated as maximising the population gains [19,20]. Modelled outcomes for 24 versus 30 CSCs across England using a discrete event simulation indicated this service recon guration would deliver health gains within current thresholds of cost-effectiveness with a very high probability of being cost-effective [20].…”